Muffler

ABSTRACT

A muffler shell of originally circular cross section is shaped into a figure eight cross section and subdivided into chambers by transverse partitions, one of the chambers acting with perforated areas in a gas flow tube to attenuate relatively low frequencies and another of the chambers containing overlapping perforated tubes defining a reverse flow or triflow path for gas passing through it.

United States Patent lnventor Donald W. Kcllicutt Horton, Mich. App]. No. 823,792 Filed May 12, 1969 Patented Feb. 16, 1971 Assignee Tenneco Inc.

Houston, Tex. a corporation of Delaware MUFFLER 9 Claims, 3 Drawing Figs.

11.8. (1 181/61, 1 81/72, 181/54 Int. Cl. F0ln 7/18, F0 1 n 1/08 FieldofSearch 181/61- [56] References Cited UNITED STATES PATENTS 2,484,816 10/1949 Culbert l81/61UX 2,897,909 8/1959 Abarth 18 l/72UX 3,135,350 6/1964 Mattie 181/61X FOREIGN PATENTS 582,946 10/1958 ltaly 181/72 Primary Examiner-Robert S. Ward, Jr. Attorney-Harness, Dickey & Pierce ABSTRACT: A muffler shell of originally circular cross section is shaped into a figure eight cross section and subdivided into chambers by transverse partitions, one of the chambers acting with perforated areas in a gas flow tube to attenuate relatively low frequencies and another of the chambers containing overlapping perforated tubes defining a reverse flow or triflow path for gas passing through it.

MUFFLER BRIEF SUMMARY OF THE INVENTION It is the purpose of this invention to provide a long, sturdy muffler of small cross-sectional areawhich is effective to remove a high level of sound energy from exhaust gas passing through it. I

The invention accomplishes this and other objects by means of a long shell of figure eight construction which is formed by shaping an originally circular tube. Gas silencing means are housed within the shell and due to its figure eight construction, a triflow arrangement of tubes 'as well as a straightthrough tube can be efiectively supported and used despite the small cross-sectional area of the muffler.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross secton through a muffler embodying the invention and showing the spout at the outlet end; FIG. 2 is an enlarged cross section along the line 2-2 of FIG. I; and

FIG. 3 is an enlarged cross section along the line 3-3 of FIG.

DESCRIPTION or THE I VENTION The muffler I has a tubular shell 3 which is closed at its inlet end by a header 5 and at its outletend by a header 7, each of which is attached in a gastight manner to its end of the shell 3. The inlet header 5 has an annular flange 9 defining an inlet opening and the outlet header 7whas an annular flange 11 defining an outlet opening for gas passage through the muffler.

As seen best in FIGS. 2 and 3,"the shell 3 is of a generally figure eight construction having sides 13 and 15 which areseparated by a minimum width center portion 17. The figure eight construction is formed by indenting and compressing or otherwise suitably shaping a tube which because of ready availability is preferably originally circular in cross section. The figure eight cross section is compact and resists undesired vibrations or distortions and desirably subdivides the space inside 'the shell 3 into the transversely adjacent and communicating axially coextensive side chambers 13 and 15.

Internal partitions 19 and 21 also of figure eight construction are positioned within the shell 3 to act with each other and with the end headers to subdivide the space within the shell into the end chambers 23 and 25 and the intermediate chamber 27. An inlet gas flow tube '29 is supported in the inlet opening flange 9 and in a flanged opening 31 in the header 19. It is positioned in the side 13 of the figure eight and opens at its outlet end into the intermediate or cross chamber 27.

Within the chamber 25 are overlapping gas flow tubes 33 and 35 each of which is open at opposite ends, the tube 33 being supported in annular flanged opening 36 in the partition 21 and the tube 35 being supported in the flanged outlet opening 11. The tubes 33 and 35 overlap throughout a substantial portion of their lengths and asubstantial portion of the overlapped sections of each tube are provided with a multitude of louvers 37 and 39 respectively. The tube 33 is disposed in the side 15 of the figure eight and its downstream end terminates a spaced axial distance from the outlet header 7; whereas the tube 35 is located in the figure eight section 13 and its upstream end is disposed a substantial distance away from the transverse partition 21. The tubes may be spotwelded to each other for mutual support as seen at 41 A bracket 43 is welded to the tube 35 and to the partition 21 to support the partition which is not spotwelded to the shell 3 as is the partition 19. It will be seen that the tubes 33 and 35 form a triflow pattern in an axial direction for gas flow through the chamber 25 with the gas also being able to pass transversely from the figure eight section 15 through the restricted cross section 17 to the figure eight section 13 to enter the inlet end of the tube 35 after having reversed its flow as it leaves the outlet end of the tube 33.

If desired, a spout 45 may be welded to the end header 7 as indicated at 47 to receive gases discharged by the tube 35. Though not shown, a similar arrangement could be attached to the inlet header 5 to surround the inlet opening 9.

The tube 29 has a first louveredarea 49 of substantial axial extent which opens into both sides of the chamber 23 and a second louvered area 51 of somewhat less axial extent also opening into both sides of the chamber 23. Due to the volume of the chamber 23 it can act by way of its acoustic connection through louvers 49 and louvers 51.to attenuate different but relatively low frequencies, it being possible to utilize each louver patch 49 and 51 along with the lengths of the chamber 23 to form quarter wave length tuning arrangements (Quinkie tuning) whereby the silencing structure in chamber 23 can be tuned to tow or three different preselected frequencies as desired or required.

A third louver path 53 is in the tube 29 and this is surrounded by an imperforate shell 55 that is mounted on the tube in a gastight manner and forms-with the louvers a spit chamber for attenuating high frequencies and roughness.

A fourth louver patch 57, which is somewhat longer in length than patch 53, is formed in the tube 29 on the other side of the louver patch 21 and it is surrounded by an imperforate shell 59 that is mounted on the tube 29 in a gastight manner to form a somewhat larger 'spit chamber for attenuating relatively high frequency roughness noises.

Hanger brackets 61 and 63 may be welded at suitable locations to the shell 3 as seen in FIGS. 1 and 2. Suitable clearance indentations 65 may also be pressed into the shell if desired.

In operation, gas enters the upstream end of the tube 29 and is discharged at its downstream end into the intermediate or cross chamber 27. It then enters the tube 33 and in passing out the downstream end of this tube reverses its direction to flow back toward the partition 21 where'it again reverses direction and enters the tube 35 and passes out through the outlet end 11 and spout 45 to atmosphere. Within the chamber 23, selected frequencies and a wide range of lower level frequencies may be attenuated by the action of the louver patches 49 and 51 with the volume of the chamber 23. High frequencies are attenuated in different ranges by the spit chamber action of the shell 55 with the louvers 53 and the shell 59 with the louvers 57. The total area of the louver patches 49 and 5l is relatively large so that the chamber 23 can also act as an expansion chamber for gas flowing through tube 29.

Within the chamber 25, the gas and sound are subjected to the effective energy removal characteristic of the triflow pattern provided by the overlapping tubes 33 and 35. Additionally the louver patches 37 and 38 act with the volume of the chamber 25 to provide a silencing effect and bypassing from one louver patch to the other to accommodate pressure conditions is also possible because of the louver arrangement.

Modifications may be made without departing from the spirit and scope of the invention.

Iclaim:

I. An exhaust gas muffler comprising an elongated tubular shell having a substantially figure eight cross section, header at opposite ends closing the interior of the shell, one of said headers having an inlet opening therein and the other having an outlet opening therein, and internal gas passage and silencing structure inside the shell to convey gas from the inlet to the and attenuate sound en route.

2. A muffler as set forth in claim 1 wherein said gas passage and silencing structure includes a first open-ended tube located in one side of the figure eight and a second openended tube overlapping the first and located in the other side of the figure eight and in series gas flow relationship with the first tube to provide a triflow pattern for gas flow.

3. A muffler as set forth in claim 2 wherein said structure includes a third open-ended tube spaced axially from the first and second located in one side of the figure eight and having a first perforated area in the wall thereof opening into the communicating with both sides of the figure eight.

4. A mufiler as set forth in claim 3 wherein said third tube has a second perforated area in the wallthereof spaced axially from the first area and opening into and communicating with both sides of the figure eight, both said-perforated areas opening into a common space within said shell extending across the full cross section thereof and along a length exceeding the length encompassed on the tube by the two areas.

5. A muffler as set forth in claim 1 wherein said gas passage and silencing structure includes an open-ended tube located in one side of the figure eight and having a perforated area in the wall thereof opening into and communicating with both sides of the figure eight.

6. An exhaust gas muffler comprising an elongated tubular shell having a substantially figure eight cross section, headers at opposite ends closing the interior of the shell one of which has an inlet opening therein and the other of which has an outlet opeiiing therein, a pair of axially spaced transverse partitions inside the shell and subdividing the interior of the shell into a pair of end chambers and an intermediate chamber which is substantially shorter in length than either of the end chambers, first and second open-ended perforated tubes located in one of said end chambers and overlapping each other axially with one of said tubes located in one side of the figure eight and the other of said tubes located in the other side of the figure eight, said first and second tubes being in series gas flow relationship in said end chamber to provide a triflow pattern for gas flow through the chamber, one of said tubes opening into said intermediate chamber and the other communicating with an opening in a header, a third tube communicating with the other opening in the other header and located in the other end chamber on a side of the figure eight, said third opening into the said intermediate chamber, said third tube having axially spaced perforated areas opening into said end chamber, said third tube having additional perforated areas and imperforate shells mounted on said third tube in said end chamber and surrounding said additional perforated areas to form high frequency sound attenuating chambers.

7. A muffler as set forth in claim 6 wherein said third tube and the other tube which opens into the intermediate chamber are located on opposite sides of the figure eight.

8. A muffler as set forth in claim 7 wherein an end of the third tube is mounted in a said opening in an end header and an end of one of the first and second tubes is mounted in said opening in the dther end header.

9. A muffler for silencing sound in flowing gases comprising an elongated shell, a gas flow tube extending longitudinally of the shell and substantially fixed in position relative to the shell, a transverse partition in the shell and spaced from said tube, and a support bracket fixed to the tube and to the partition whereby said tube supports said partition in a substantially fixed position. 

1. An exhaust gas muffler comprising an elongated tubular shell having a substantially figure eight cross section, header at opposite ends closing the interIor of the shell, one of said headers having an inlet opening therein and the other having an outlet opening therein, and internal gas passage and silencing structure inside the shell to convey gas from the inlet to the and attenuate sound en route.
 2. A muffler as set forth in claim 1 wherein said gas passage and silencing structure includes a first open-ended tube located in one side of the figure eight and a second open-ended tube overlapping the first and located in the other side of the figure eight and in series gas flow relationship with the first tube to provide a triflow pattern for gas flow.
 3. A muffler as set forth in claim 2 wherein said structure includes a third open-ended tube spaced axially from the first and second located in one side of the figure eight and having a first perforated area in the wall thereof opening into the communicating with both sides of the figure eight.
 4. A muffler as set forth in claim 3 wherein said third tube has a second perforated area in the wall thereof spaced axially from the first area and opening into and communicating with both sides of the figure eight, both said perforated areas opening into a common space within said shell extending across the full cross section thereof and along a length exceeding the length encompassed on the tube by the two areas.
 5. A muffler as set forth in claim 1 wherein said gas passage and silencing structure includes an open-ended tube located in one side of the figure eight and having a perforated area in the wall thereof opening into and communicating with both sides of the figure eight.
 6. An exhaust gas muffler comprising an elongated tubular shell having a substantially figure eight cross section, headers at opposite ends closing the interior of the shell one of which has an inlet opening therein and the other of which has an outlet opening therein, a pair of axially spaced transverse partitions inside the shell and subdividing the interior of the shell into a pair of end chambers and an intermediate chamber which is substantially shorter in length than either of the end chambers, first and second open-ended perforated tubes located in one of said end chambers and overlapping each other axially with one of said tubes located in one side of the figure eight and the other of said tubes located in the other side of the figure eight, said first and second tubes being in series gas flow relationship in said end chamber to provide a triflow pattern for gas flow through the chamber, one of said tubes opening into said intermediate chamber and the other communicating with an opening in a header, a third tube communicating with the other opening in the other header and located in the other end chamber on a side of the figure eight, said third opening into the said intermediate chamber, said third tube having axially spaced perforated areas opening into said end chamber, said third tube having additional perforated areas and imperforate shells mounted on said third tube in said end chamber and surrounding said additional perforated areas to form high frequency sound attenuating chambers.
 7. A muffler as set forth in claim 6 wherein said third tube and the other tube which opens into the intermediate chamber are located on opposite sides of the figure eight.
 8. A muffler as set forth in claim 7 wherein an end of the third tube is mounted in a said opening in an end header and an end of one of the first and second tubes is mounted in said opening in the other end header.
 9. A muffler for silencing sound in flowing gases comprising an elongated shell, a gas flow tube extending longitudinally of the shell and substantially fixed in position relative to the shell, a transverse partition in the shell and spaced from said tube, and a support bracket fixed to the tube and to the partition whereby said tube supports said partition in a substantially fixed position. 